Effects of proximal grooves and abutment height on the resistance of resin-cemented crowns in teeth with inadequate resistance: An in vitro study

Biomed J. Jul-Aug 2015;38(4):336-41. doi: 10.4103/2319-4170.148905.

Abstract

Background: The resistance form is a key factor for a successful crown fabrication. This in vitro study evaluates the effects of proximal grooves and abutment height on the resistance of single cast crowns in molars with inadequate resistance.

Methods: Sixty extracted human molars were prepared to possess 20° of total occlusal convergence for single crown fabrication. All of the prepared teeth were divided into six groups and prepared according to three axial heights (2, 3, and 4 mm) with or without preparing a pair of proximal grooves. Alloy metal copings of 5% titanium were casted and cemented. A self-adhesive modified-resin cement was used for cementation. A lateral dislodgement test was performed with an increasing external force applied at a 45° angulation on a universal testing machine. The force required to dislodge the crown from the tooth or to break the core was recorded.

Results: Proximal grooves increased the dislodgement resistance in groups with an abutment height of 4 mm, whereas adding grooves made no significant differences in resistance in groups with abutment heights of 2 and 3 mm. The 2 mm groups exhibited worse performance than the other groups, whether they had proximal grooves or not.

Conclusion: An abutment height of 3 mm provided adequate resistance for single cast crowns when self-adhesive modified-resin cement was used. Preparing a pair of proximal grooves on abutments shorter than 4 mm had no significant influence on the resistance.

MeSH terms

  • Cementation* / methods
  • Crowns*
  • Humans
  • Resin Cements*
  • Stress, Mechanical
  • Tooth / physiology
  • Tooth / surgery*
  • Tooth Preparation* / methods

Substances

  • Resin Cements